.TH tcplife 8  "2016-10-19" "USER COMMANDS"
.SH NAME
tcplife \- Trace TCP sessions and summarize lifespan. Uses Linux eBPF/bcc.
.SH SYNOPSIS
.B tcplife [\-h] [\-T] [\-t] [\-w] [\-s] [\-p PID] [\-D PORTS] [\-L PORTS]
.SH DESCRIPTION
This tool traces TCP sessions that open and close while tracing, and prints
a line of output to summarize each one. This includes the IP addresses, ports,
duration, and throughput for the session. This is useful for workload
characterisation and flow accounting: identifying what connections are
happening, with the bytes transferred.

This tool works using the sock:inet_sock_set_state tracepoint if it exists,
added to Linux 4.16, and switches to using kernel dynamic tracing for older
kernels. Only TCP state changes are traced, so it is expected that the
overhead of this tool is much lower than typical send/receive tracing.

Since this uses BPF, only the root user can use this tool.
.SH REQUIREMENTS
CONFIG_BPF and bcc.
.SH OPTIONS
.TP
\-h
Print usage message.
.TP
\-s
Comma separated values output (parseable).
.TP
\-t
Include a timestamp column (seconds).
.TP
\-T
Include a time column (HH:MM:SS).
.TP
\-w
Wide column output (fits IPv6 addresses).
.TP
\-p PID
Trace this process ID only (filtered in-kernel).
.TP
\-L PORTS
Comma-separated list of local ports to trace (filtered in-kernel).
.TP
\-D PORTS
Comma-separated list of destination ports to trace (filtered in-kernel).
.SH EXAMPLES
.TP
Trace all TCP sessions, and summarize lifespan and throughput:
#
.B tcplife
.TP
Include a timestamp column, and wide column output:
#
.B tcplife \-tw
.TP
Trace PID 181 only:
#
.B tcplife \-p 181
.TP
Trace connections to local ports 80 and 81 only:
#
.B tcplife \-L 80,81
.TP
Trace connections to remote port 80 only:
#
.B tcplife \-D 80
.SH FIELDS
.TP
TIME
Time of the call, in HH:MM:SS format.
.TP
TIME(s)
Time of the call, in seconds.
.TP
PID
Process ID
.TP
COMM
Process name
.TP
IP
IP address family (4 or 6)
.TP
LADDR
Local IP address.
.TP
RADDR
Remote IP address.
.TP
LPORT
Local port.
.TP
RPORT
Remote port.
.TP
TX_KB
Total transmitted Kbytes.
.TP
RX_KB
Total received Kbytes.
.TP
MS
Lifespan of the session, in milliseconds.
.SH OVERHEAD
This traces the kernel TCP set state function, which should be called much
less often than send/receive tracing, and therefore have lower overhead. The
overhead of the tool is relative to the rate of new TCP sessions: if this is
high, over 10,000 per second, then there may be noticeable overhead just to
print out 10k lines of formatted output per second.

You can find out the rate of new TCP sessions using "sar \-n TCP 1", and
adding the active/s and passive/s columns.

As always, test and understand this tools overhead for your types of
workloads before production use.
.SH SOURCE
This is from bcc.
.IP
https://github.com/iovisor/bcc
.PP
Also look in the bcc distribution for a companion _examples.txt file containing
example usage, output, and commentary for this tool.
.SH OS
Linux
.SH STABILITY
Unstable - in development.
.SH AUTHOR
Brendan Gregg
.SH SEE ALSO
tcpaccept(8), tcpconnect(8), tcptop(8)
